slapos_subscription_request: Add missing property sheet for Subscription Request

To enable get/setTextContent

master/bt5/slapos_subscription_request/PortalTypePropertySheetTemplateItem/property_sheet_list.xml

@@ -12,6 +12,7 @@
   <item>SlapOSAccountingHostingSubscriptionConstraint</item>
   <item>SlaposHostingSubscriptionConstraint</item>
   <item>SoftwareInstance</item>
+  <item>TextDocument</item>
   <item>Url</item>
   <item>VariationRange</item>
  </portal_type>

master/bt5/slapos_subscription_request/bt/template_portal_type_property_sheet_list

@@ -8,6 +8,7 @@ Subscription Request | Person
 Subscription Request | SlapOSAccountingHostingSubscriptionConstraint
 Subscription Request | SlaposHostingSubscriptionConstraint
 Subscription Request | SoftwareInstance
+Subscription Request | TextDocument
 Subscription Request | Url
 Subscription Request | VariationRange
 Trial Condition | HostingSubscription